How Is a Fire Scene Investigated?
All that remains is ash and soot — but to an experienced investigator, it is an open book. Fire investigator Yunus Kızmaz, drawing on 33 years of crime and fire scene investigation, explains how he determines where a fire originated, whether it was accidental or deliberate arson, and how to read the indelible marks etched into the floor. In the second half: the life-saving precautions these forensic findings prove indispensable.
30-Second Summary
- Every fire has a distinct point of origin. The investigator tracks heat and soot gradients backwards against the path of spread to isolate it — the area with the most severe damage and the "cleanest" burn is usually where it began.
- The indelible "henna pattern" (rust pour trail) revealed after washing the floor is permanent physical proof that a liquid accelerant was poured to set the fire — no detergent can remove it.
- In electrical fires, the copper cable speaks volumes: arc beading, fusion welding, and dark cherry oxidation point to high overcurrent; brittle copper that crumbles in your hand indicates prolonged overheating. Both are verified in the laboratory via SEM and GC-MS.
- If the distribution panel lacks a 300 mA fire-protection RCD (mandated by Art. 18 of the Electrical Internal Installations Regulation), legal liability is established. Most pre-2007 buildings lack this relay, and Court of Cassation precedent treats its absence as primary fault.
- The signatures of insurance arson are unmistakable: an insurance policy written for several times the facility's true value, security cameras disabled on the night of the incident, multiple independent points of origin, and anomalous items such as an improvised mechanical clock delay device.
- The second half: these field findings prove beyond debate why fire compartmentation, non-combustible cladding, automatic suppression, and trained on-site staff are non-negotiable safeguards.
In What Systematic Order Does an Investigator Read the Scene?
Fire scene investigation is an exacting forensic discipline requiring rigorous training, deep scientific knowledge, and extensive field experience. Once the fire brigade has completed suppression and withdrawn, the investigator steps in and always follows the exact same sequence. Each step narrows the investigative scope for the next.
Cause of Ignition + Attribution of Fault
Field findings are synthesized with laboratory and metallurgical data to conclusively establish the point of origin, the ignition cause, and liability. The findings are formulated into a formal expert witness report pursuant to Turkish Code of Civil Procedure (HMK Art. 293), serving as the technical bedrock for prosecutors and courts.
The "Henna Pattern" (Pour Trail): The Indelible Mark of Arson
At the initial point where a fire ignites, ambient oxygen is abundant (around 20–21%). Due to this rich oxygen supply, combustible items directly at the origin burn almost completely away, leaving behind a characteristic "clean burn" zone free of carbon soot. As the fire expands away from the center, oxygen is depleted and heavy, velvety soot begins coating walls, ceilings, and surrounding items. The investigator reads this gradient: the focal area exhibiting the deepest structural consumption combined with clean burning marks the true point of origin.
When arson is committed using a liquid accelerant — such as lacquer thinner, mineral spirits, gasoline, or benzene — the perpetrator typically pours it from a can in a continuous trail leading from the origin out toward the exit door. Upon stepping out, they ignite the trail; the flame races backward along the liquid path like a gunpowder fuse straight to the epicenter.
Once fire debris and ash are completely shoveled out and the subfloor (whether hardwood, ceramic tile, or reinforced concrete) is washed down, that pour trail leaves behind a distinct reddish-brown rust oxidation mark — widely known in Turkish forensic jargon as the "henna pattern" (kına paterni). Regardless of the fire's peak temperature, duration, or total fuel load, this rust stain is permanently etched into the mineral structure of the floor; scrub it with industrial detergents and it will not fade. Here the investigator speaks with absolute forensic certainty: "This premises was deliberately torched."
“No matter how massive the fire, and no matter how vigorously you scrub with detergents, that rust pour stain cannot be removed. We state unequivocally: this property was intentionally set on fire.”
- The fire was intentionally set using a liquid accelerant poured in a deliberate trail from the origin toward the exit.
- The incident is formally classified as a "suspicious fire / probable arson"; establishing the perpetrator's identity and criminal intent rests with the public prosecutor and law enforcement.
- "Henna pattern", liquid accelerant pour trail, or continuous oxidation rust band — all denote the exact same conclusive physical evidence.
The Hallmarks of Arson and Insurance Fraud
Natural, accidental, and electrical fires almost invariably develop progressively and spread outward from a single point. Arson, by contrast, leaves a fundamentally distinct physical signature. When commercial facility owners face severe financial insolvency, some insure their premises for figures vastly exceeding its real market value and arrange to have it burned down — either personally or via recruited accomplices. This is known as insurance arson. Identifying its hallmarks is rarely difficult for a trained investigator.
Inflated Policy Limits + Disabled Surveillance
The facility is insured far above its tangible asset value — commonly 3 to 5 times, and in egregious cases up to 10 times its true worth. On the night of the fire, the CCTV recording system is conveniently turned off or unplugged, and the night watchman is granted sudden leave.
- Coverage limits grossly disconnected from real value
- Security cameras switched off that evening
- Night watchman unexpectedly granted time off
Multiple Independent Points of Origin
Accidental fires originate from a single focal point. The discovery of several separate, simultaneous points of origin within the same facility — with no thermal or flame propagation connection between them — is on its own indisputable evidence of deliberate arson.
- Distinct, isolated origin points
- Absence of fire spread bridges between points
- Separate liquid accelerant residues detected at each site
Improvised Time-Delay Ignition Devices
Perpetrators construct mechanical delay devices to secure an alibi and buy time to flee: a cord tied to the winding key of a mechanical wind-up clock slowly draws a thick pillar candle closer, rotation by rotation, toward a plastic bag suspended with gasoline. Half an hour later, the plastic bag melts, the fuel cascades down, and a raging blaze erupts.
- Melted mechanical clockwork anomalous in the debris
- Residues of heavy decorative pillar candles
- Liquid accelerant / henna oxidation trails on the floor
A Commercial Facility Torched from Four Independent Corners
Following a major fire reported at an industrial enterprise along the Sivas–Erzincan highway, the court impaneled a four-member forensic commission comprising a Gendarmerie crime scene investigation team, a university professor, and Yunus Kızmaz. The roof and walls had collapsed, and heavy snow filled the smoldering ruins. Once the floor was completely cleared of debris and washed down, forensic examination revealed that the facility had been ignited simultaneously from four completely separate corners. Further inquiry revealed that the business had secured an insurance policy ten times its tangible value, had cut power to the security cameras on the night of the blaze, and had instructed the night watchman not to report for duty.
A forensic panel does not accuse a specific suspect — establishing criminal culpability is the exclusive purview of the judicial investigation. However, every piece of physical and metallurgical evidence proved that the facility had been deliberately torched from within. Basing its decision directly on the forensic causation established in the report, the insurance carrier denied the claim in full.
What Does the Copper Cable Reveal?
In metropolitan fire statistics (such as Istanbul Fire Department records), electrical malfunctions account for approximately 25–26% of all structural fires. In investigating electrical fires, the specialist first isolates the point of origin, then traces circuits backward toward the distribution source. Physical and metallurgical transformations in the phase, neutral, and protective grounding conductors reveal with certainty whether the fire began within the electrical circuit or whether the cable was merely engulfed by an external blaze.
Arc Beading and Fusion Welding
Conductors welded together, localized copper globules resembling small beads (arc beads), and a distinctive dark cherry tarnish indicate localized electrical arcing under heavy overcurrent. For instance, when a motor bearing loses lubrication and seizes, the motor draws massive amperage; the conductors heat rapidly, insulation degrades to its auto-ignition temperature, and catastrophic failure ensues.
Brittle Copper That Crumbles in Your Hand
Solid single-strand copper conductors subjected to sustained overcurrent (such as 4 mm² NYA wiring) do not necessarily weld together, but undergo severe metallurgical annealing, becoming extremely brittle. When handled, the copper snaps and crumbles effortlessly. This demonstrates that the conductor sustained extreme thermal overcurrent, destroying its copper ductility — often conclusive even prior to laboratory testing.
External Flame Impingement (Consequence, Not Cause)
If the copper conductors have retained their mechanical ductility and the circuit run originated outside the burn zone, the fire almost certainly spread from an external fuel package, consuming the cables and their PVC insulation from the outside in. In this scenario, the damaged cable is a casualty of the fire, not its cause.
Cable specimens are sent to specialized metallurgical laboratories at Yıldız Technical University and Istanbul Technical University. Under a Scanning Electron Microscope (SEM), the crystalline boundary structure of the copper differentiates with 100% certainty between a primary short circuit that caused the fire versus secondary short-circuit melting caused by external fire exposure. Concurrently, fire debris, soot swabs, and runoff water samples are analyzed via Gas Chromatography-Mass Spectrometry (GC-MS) and HPLC to detect trace volatile accelerants (gasoline, thinners, industrial solvents) or retardants (such as paraffin wax).
Two Critical Relays in the Electrical Panel — They Are Not the Same Device
Fire-Protection Residual Current Device (RCD)
300 mAEngineered to sense hazardous earth fault currents, arc tracking, and compromised insulation, cutting the circuit in approximately 0.3 seconds before leakage currents can ignite surrounding building materials (~30W threshold). It is typically installed at the main breaker output immediately after the utility meter. Mandated by Article 18 of the Electrical Internal Installations Regulation, it is conspicuously absent in most pre-2007 buildings. The Turkish Court of Cassation consistently assesses the presence or absence of this device as the primary legal determinant in apportioning fault.
Personal-Protection Residual Current Device (Life Safety RCD)
30 mAInstalled within secondary distribution sub-panels as a life-safety mechanism: if a human touches an energized appliance casing or exposed live conductor, it trips the circuit in roughly 0.3 seconds, keeping fault currents well below ventricular fibrillation thresholds to prevent fatal electrocution. However, it cannot monitor high-amperage feeder fire hazards and cannot substitute for a 300 mA fire-protection RCD.
If neither protection device is installed, legal and financial fault is assigned to the building manager / owner and the electrical distribution utility legally tasked with enforcing compliance.
What the Evidence Demands: The Life-Saving Precautions
The common denominator across more than 9,000 investigated fire and explosion cases: an ostensibly minor oversight or budget cut that ultimately destroys tens of millions in national wealth and claims human lives. The preventative measures detailed below are non-negotiable — every single one represents a deficiency repeatedly uncovered at fatal fire scenes.
Proactive Fire Engineering: Prevention Before Catastrophe
Business owners routinely witness thirty years of accumulated wealth vanish into ash within thirty minutes. For industrial plants, logistics warehouses, multi-tenant commercial centers, and production workshops, conducting an independent pre-fire feasibility audit followed by recurring inspections is literally a matter of survival.
Pre-Fire Feasibility Audit + Monthly Compliance Inspections
Pursuant to the Regulation on the Protection of Buildings from Fire, an exhaustive engineering audit must be commissioned from a certified fire safety consultancy to identify and remediate regulatory violations, followed by mandatory monthly advisory and inspection visits.
Unobstructed Fire Escapes and Smoke-Tightly Compartmented Zones
A fire stairwell that is carpeted, locked, or used to store inventory guarantees fatalities during a fire. Conversely, a certified fire compartment is a structurally isolated refuge capable of resisting fire and toxic smoke for 1 to 1.5 hours, supplied with positive-pressure fresh air. In hospitals, high-rise hotels, and mines — where occupants cannot swiftly evacuate independently — compartmentation is mandatory under fire codes.
Non-Combustible Exterior Cladding and Interior Linings
Expanded polystyrene (EPS) and polyurethane foam insulation panels used in wedding halls, cinemas, and building facades undergo destructive thermal pyrolysis during a fire, melting into fiery droplets, saturating corridors with lethal hydrogen cyanide and carbon monoxide, and cutting off escape. Building codes mandate non-combustible rock wool or glass wool (Class A1/A2); while material costs differ, human life cannot be compromised for a balance sheet.
Certified Automatic Suppression Systems
Commercial kitchen hoods require dedicated automatic wet chemical or clean-agent suppression; storage and production facilities spanning 2,000 m² and above require automatic wet-pipe sprinkler systems (with no square-footage exemption for chemical, paint, or highly flammable production); chemical plants require specialized foam deluges. For main and distribution electrical panels, direct in-panel automatic clean-agent (such as FM-200) tubing extinguishes micro-arcs before flame can escape the enclosure. Conventional CO₂ cylinders are restricted in many indoor occupancies due to life-safety asphyxiation and environmental concerns.
Mandatory Periodic Exhaust Duct & Flue Degreasing
In restaurants, cafes, and commercial kitchens operating deep fryers, vaporized cooking oils coalesce into thick combustible grease layers inside hoods and extraction ductwork. When ignited, these ducts transform into blazing horizontal chimneys that spread fire across multiple floors within minutes. Ducts must be thoroughly degreased and certified by licensed specialists at intervals specified by fire regulations.
Structured Staff Drills and Dedicated On-Site Fire Brigades
During the major hotel fire at the Kartalkaya mountain resort, municipal fire brigades required 55 minutes simply to arrive on scene due to altitude and blizzard conditions; had an on-site detachment existed in the resort zone, the fire could have been contained within minutes. Large industrial complexes and remote resort chains must establish seasonal internal fire detachments and conduct three-tier drills (pre-fire preparedness, active crisis evacuation, and post-fire control) for all personnel.
It Is Not the Flame That Kills You — It Is the Smoke
In any enclosed structural fire, the growing combustion plume draws surrounding oxygen into the flame front. Ambient oxygen, which begins at a healthy 21%, plummets rapidly. Even if you are located 70 meters away from the flames or on an upper floor, toxic smoke travels at speeds exceeding 1 to 2 meters per second. As smoke banks down, oxygen levels fall below survivable thresholds, causing victims to lose consciousness and collapse where they stand.
/// Simultaneously, the atmosphere becomes saturated with lethal concentrations of carbon monoxide (CO), hydrogen cyanide (HCN), and hydrochloric acid (HCl) gas from burning synthetic polymers. These systemic poisons induce brain death far faster than carbon dioxide.
The Crucial First 3 Minutes: What to Do
- Never turn back for your phone, wallet, or luggage — a tragic percentage of fatalities occur when victims re-enter smoke to retrieve personal items.
- Buoyant superheated gases collect at the ceiling and gradually bank down; cooler, breathable air persists near the floor for a few critical extra minutes.
- Never stand erect and run through smoke; drop to hands and knees, crawl low, or advance in a low "duck walk" beneath the thermal layer.
- If escape is cut off: seal windows and doors, shut off electrical circuit breakers, notify the fire brigade of your exact room location, block door under-gaps with wet towels, and signal rescuers from an exterior window.
“Our business owners tragically watch thirty years of accumulated life savings vanish in thirty minutes. We witness this tragedy repeatedly in the field. What is being destroyed is the national wealth — it must not be squandered to preventable neglect.”
Frequently Asked Questions
How does an investigator locate the exact point of origin of a fire?+
What is the "henna pattern" (pour trail) and why can it not be washed away?+
How do forensic investigators distinguish an electrical fire from arson?+
What is the difference between a 300 mA fire-protection RCD and a 30 mA residual-current relay?+
How is insurance arson proven at a fire scene?+
What should I do if a fire breaks out and cannot be immediately extinguished?+
What is fire compartmentation and why is it essential?+
When Should You Retain an Independent Fire Forensics Expert?
If any of the following scenarios applies to your situation, never proceed into insurance negotiations or judicial proceedings without commissioning an independent forensic scene and liability analysis.
Yunus Kızmaz
Over 40 years of field command in civil defence, search-and-rescue, and municipal fire services since 1980; court-certified forensic expert witness since 1992. Senior fire and explosion investigator with over 9,000 completed forensic scene examinations and court reports. Lecturer in crime scene forensics, counter-terrorism, and explosion dynamics at Bishkek Manas University and the Istanbul Police Academy; instructor of "Advanced Fire Scene Investigation Techniques" to metropolitan fire departments.